Due to its thin, lightweight, flexible and durable properties, graphene has enjoyed a wide range of applications. For example, graphene has been used in biological engineering, optical electronics, ultrafiltration, composite materials, photovoltaic cells, energy storage devices, and/or the like.
Recent discoveries of the potential applications of graphene have spurred increased interest in developing large scale graphene manufacturing applications that produce graphene that is free or substantially free of defects, such as graphite deposits on the graphene sheet. Previous methods included cutting blocks of graphite into the thin graphene sheets. Such methods included obtaining a thin graphene sheet by placing an adhesive substrate (such as tape) against the graphite and removing the graphene. While such methods may be useful for analysis, they may not be suitable for large scale graphene manufacturing because of the small amount of graphene that is obtained.
Other methods have involved oxidizing graphite to produce graphene oxide, which is then solubilized. The graphene oxide is precipitated to produce sheets of graphene. However, these methods result in flawed graphene sheets because bergs of graphite are present on the graphene sheet. Accordingly, the graphene sheet is not free of defects.
Other methods include sonicating and centrifuging graphite to yield graphene, forming epitaxial graphene on diamond surfaces, forming epitaxial graphene on metal surfaces, and decomposing the surface of silicon carbide. However, each of these methods results in graphene sheets that have defects and/or are not suited for large scale use.